Blends of a poly(aryl ether ketone) and a polyarylate

ABSTRACT

Described are blends of a crystalline poly(aryl ether ketone) and a polyarylate and/or a liquid crystalline polyarylate. These blends exhibit improved mechanical properties and environmental stress rupture resistance.

This is a division, of application Ser. No. 295,114, filed Jan. 9, 1989,which is a continuation of Ser. No. 087,175 filed Aug. 17, 1987,abandoned, which is a continuation of Ser. No. 797,765 filed Nov. 14,1985, abandoned, which is a continuation of Ser. No. 625,915 filed June29, 1984, abandoned.

BACKGROUND OF THE INVENTION

This invention is directed to a blend of a crystalline poly(aryl etherketone) and a polyarylate and/or a liquid crystalline polyarylate. Theseblends exhibit improved mechanical properties and environmental stressrupture resistance.

Poly(aryl ether ketones) are high performance materials which are usefulfor various demanding applications. They offer a combination ofexcellent thermal stability, hydrolytic stability, excellent chemicaland environmental stress rupture resistance. This combined with veryhigh crystalline melting points yields a property balance not availablewith other classes of polymers.

In the early 1980's, a poly(aryl ether ketone) of the following formulawas made commercially available, e.g. U.S. Pat. No. 4,320,224: ##STR1##

The poly(aryl ether ketone) of the following formula is known from theliterature, e.g. U.S. Pat. No. 3,956,240: ##STR2##

Another poly(aryl ether ketone) which was available commercially is ofthe following formula. e.g. U.S. Pat. No. 3,953,400: ##STR3##

The poly(aryl ether ketones) are crystalline polymers which exhibit highmelting points. Due to their high melting points, high processingtemperatures are required (>300° C.) in order to fabricate the polymer.Few polymeric materials currently available are stable enough to beblended with the poly(aryl ether ketones) at such high temperatures.

Polyarylates are aromatic polyesters, many of which are derived from adihydric phenol, particularly 2,2-bis(4-hydroxyphenyl) propane (alsoidentified as Bisphenol-A) and an aromatic dicarboxylic acid(s),particularly mixtures of terephthalic and isophthalic acids. A preferredpolyarylate is of the following formula: ##STR4##

Polyarylates are high temperature, high performance thermoplasticpolymers with a good combination of thermal and mechanical propertiesincluding high impact strength. The polyarylates have good meltstability at high temperatures.

In the present invention it has been found that a blend of a poly(arylether ketone) and a polyarylate has both a notched izod impact strengthand tensile impact strength which is significantly higher than that ofeither of the unblended constituents. Further, the addition of poly(arylether ketone) to polyarylate results in a significant improvement in theenvironmental stress rupture resistance of the polyarylate. Also, theaddition of a liquid crystalline polyarylate to a poly(aryl etherketone) leads to improved strength.

U.S. Pat. No. 4,438,236 issued Mar. 20, 1984 describes a compositioncontaining a melt-processable polymer and an anisotropic melt-formingpolymer. Specifically, Example 6 describes blending apolyether-etherketone with a liquid crystal polyester which was copoly(chloro-1,4-phenylene ethylene dioxy-4,4'dibenzoate) terephthalate. Thisexample states that this blend has a significant reduction in meltviscosity as compared to the polyetheretherketone polymer itself.

However, it has been found that the addition of liquid crystallinepolyarylates to poly(aryl ether ketone)s leads to a decrease in meltflow (increase in viscosity) at both low and high shear rates. Theblends of this invention exhibit a higher viscosity than the constituentpolymers. This is contrary to the disclosure of U.S. Pat. No. 4,438,236,which states that the addition of small amounts of liquid crystallinepolymers to many diverse polymer systems leads to increased melt flow(decreased viscosity). In the instant blend, some unexpected interactionbetween the liquid crystalline polyarylate and the poly(aryl etherketone) must be occurring.

European Patent Application No. 59077 published Sept. 1, 1982 describesa method for the orientation of films made from a thermoplasticpolyether ether ketone. This publication states that the polymer mayalso contain, for the purpose of improving the fluidity in extrusionprocessing, up to 50 wt. % of heat resistant polymers such aspolyarylene polyether polysulfone, polyarylate, polyester, nylon orpolycarbonate, or a polyolefin such as polyethylene or polypropylene.However, many of these blends would not be stable at the temperaturesneeded to mold the blend.

THE INVENTION

This invention is directed to a blend comprising a crystalline poly(arylether ketone) and a polyarylate and/or a liquid crystalline polyarylate.

The poly(aryl ether ketone) is used in amounts of from about 5 to about95, preferably from about 10 to about 80 weight percent, and thepolyarylate and/or liquid crystalline polyarylate is used in amounts offrom about 5 to about 95, preferably from about 20 to about 90 weightpercent.

The Poly(aryl ether ketone)

The crystalline poly(aryl ether ketone)s which are suitable for useherein can be generically characterized as containing a repeating unitof one or more of the following formulae: ##STR5## wherein Ar isindependently a divalent aromatic radical selected from phenylene,biphenylene or naphthylene, X is independently ##STR6## or a direct bondand n is an integer of from 0 to 3, b, c, d and e are 0 or 1 and a is aninteger of 1 to 4 and preferably d is 0 when b is 1.

Preferred poly(aryl ketone)s include those having a repeating unit ofthe formula: ##STR7##

These poly(aryl ketone)s are prepared by methods well known in the art.One such method comprises heating a substantially equimolar mixture ofat least one bisphenol and at least one dihalobenzoid compound or atleast one halophenol compound as described in Canadian Patent No.847,963. Preferred bisphenols in such a process include:

hydroquinone,

4,4'-dihydroxybenzophenone,

4,4'-dihydroxybiphenyl, and

4,4'-dihydroxydiphenyl ether.

Preferred dihalo and dihalobenzoid compounds include:

4-(4-chlorobenzoyl)phenol,

4,4'-difluorobenzophenone,

4,4'-dichlorobenzophenone,

4-chloro-4'-fluorobenzophenone, ##STR8##

The poly(aryl ketone)s may be produced by the process as described in,for example, U.S. Pat. No. 4,176,222. This process comprises heating inthe temperature range of 100° to 400° C., (i) a substantially equimolarmixture of (a) at least one bisphenol and (b) at least onedihalobenzenoid compound, or (ii) at least one halophenol, in which inthe dihalobenzenoid compound or halophenol, the halogen atoms areactivated by --CO-- groups ortho or para thereto, with a mixture ofsodium carbonate or bicarbonate and a second alkali metal carbonate orbicarbonate, the alkali metal of said second alkali metal carbonate orbicarbonate having a higher atomic number than that of sodium, theamount of said second alkali metal carbonate or bicarbonate being suchthat there are 0.001 to 0.2 gram atoms of said alkali metal of higheratomic number per gram atom of sodium, the total amount of alkali metalcarbonate or bicarbonate being such that there is at least one alkalimetal atom for each phenol group present, and thereafter separating thepolymer from the alkali metal halide.

Also, poly(aryl ketone)s such as those containing repeating units of theformula: ##STR9## may be produced by Friedel-Craft reactions utilizinghydrogen fluoride-boron trifluoride catalysts as described, for example,in U.S. Pat. No. 3,953,400.

Additionally, poly(aryl ketones) of the following formula: ##STR10## maybe prepared by Friedel-Craft reactions using a boron fluoride-hydrogenfluoride catalyst as described in, for example, U.S. Pat. Nos.3,441,538; 3,442,857 and 3,516,966.

The polyketones may also be prepared according to the process asdescribed in, for example, U.S. Defensive Publication No. T 103,703 andU.S. Pat. No. 4,396,755. In this process, reactants such as (a) anaromatic monocarboxylic acid, (b) a mixture of at least one aromaticdicarboxylic acid, and (c) combinations of (a) and (b) are reacted inthe presence of a fluoroalkane sulphonic acid, particularlytrifluoromethane sulphonic acid.

Additionally, poly(aryl ketone)s of the following formulas: ##STR11##may also be prepared according to the process as described in, forexample, U.S. Pat. No. 4,398,020. In such a process,

(a) a mixture of substantially equimolar amounts of

(i) at least one aromatic diacyl halide of the formula

    YOC--Ar--COY

where --Ar-- is a divalent aromatic radical, Y is halogen and COY is anaromatically bound acyl halide group, which diacyl halide ispolymerizable with at least one aromatic compound of (a)(ii), and

(ii) at least one aromatic compound of the formula

    H--Ar'--H

where --Ar'-- is a divalent aromatic radical and H is an aromaticallybound hydrogen atom, which compound is polymerizable with at least onediacyl halide of (a)(i), and

(b) at least one aromatic monoacyl halide of formula

    H--Ar"--COY

where --Ar"-- is a divalent aromatic radical and H is an aromaticallybound hydrogen atom, Y is halogen, and COY is an aromatically bound acylhalide group, which monoacyl halide is self-polymerizable, and

(c) a combination of (a) and (b) in the presence of a fluoroalkenesulphonic acid.

The term poly(aryl ether ketone) as used herein is meant to includehomopolymers, copolymers, terpolymers, graft copolymers, and the like.For example, any one or more of the repeating units (I) to (V) may becombined to form copolymers, etc.

The poly(aryl ether ketone)s have a reduced viscosity of at least about0.4 to about 5.0 dl/g, as measured in concentrated sulphuric acid at 25°C.

Polyarylates

The polyarylates which are suitable for use in this invention arederived from a dihydric phenol and at least one aromatic dicarboxylicacid and have a reduced viscosity of from about 0.4 to greater thanabout 1.0, preferably from about 0.6 to about 0.8 dl/gm, as measured inchloroform (0.5 g/100 ml chloroform) or other suitable solvent at 25° C.

A particularly desirable dihydric phenol is of the following formula:##STR12## wherein Y is selected from, hydrogen, alkyl groups of 1 to 4carbon atoms, chlorine or bromine, each z, independently, has a value offrom 0 to 4, inclusive, and R₁ is a divalent saturated or unsaturatedaliphatic hydrocarbon radical, particularly an alkylene or alkylideneradical having from 1 to 6 carbon atoms, or a cycloalkylidene orcycloalkylene radicals having up to and including 9 carbon atoms, O,SO₂, or S. The dihydric phenols may be used individually or incombination.

The aromatic dicarboxylic acids that may be used in this inventioninclude terephthalic acid, isophthalic acid, any of the naphthalenedicarboxylic acids and mixtures thereof, as well as alkyl substitutedhomologs of these carboxylic acids, wherein the alkyl group containsfrom 1 to about 4 carbon atoms, and acids containing other inertsubstituents, such as halides, alkyl or aryl ethers, and the like.Acetoxybenzoic acid can also be used. Preferably, mixtures ofisophthalic and terephthalic acids are used. The isophthalic acid toterephthalic acid ratio in the mixture is about 0:100 to about 100:0,while the most preferred acid ratio is about 75:25 to about 50:50. Also,from about 0.5 to about 20 percent of aliphatic diacids containing from2 to about 10 carbon atoms, such as adipic acid, sebacic acid, and thelike may be additionally used in the polymerization reaction.

The polyarylates of the present invention can be prepared by any of thewell known prior art polyester forming reactions, such as the reactionof the acid chlorides of the aromatic dicarboxylic acids with thedihydric phenols; the reaction of the diaryl esters of the aromaticdicarboxylic acids with the dihydric phenols; or the reaction of thearomatic diacids with diester derivatives of the dihydric phenol. Theseprocesses are described in, for example, U.S. Pat. Nos. 3,317,464;3,948,856; 3,780,148; 3,824,213; and 3,133,898.

The polyarylates of this invention include poly(arylate carbonates)which are produced by reacting a dihydric phenol with an aromatic diacidand a diaryl carbonate, such as diphenyl carbonate or carbonyl chlorideby methods well known in the art.

Liquid Crystalline Polyarylate

The liquid crystalline polyarylates which may be used herein are wellknown in the art. These liquid crystalline polyarylates are describedin, for example, U.S. Pat. Nos. 3,804,805; 3,637,595; 3,845,099;3,318,842; 4,076,852; 4,130,545; 4,161,470; 4,230,817 and 4,265,802.Preferably, the liquid crystalline polyarylates are derived from one ormore of the following: p-hydroxy benzoic acid, m-hydroxy benzoic acid,terephthalic acid, isophthalic acid, hydroquinone, resorcinol,4,4'-biphenol, 2,6-naphthalene diol, 2,6-naphthalene dicarboxylic acid,6-hydroxy-2-naphthoic acid and 2,6-dihydroxy anthraquinone moreparticularly, U.S. Pat. No. 3,637,595 discloses a polyester of recurringmoieties of Formulae I, II and III: ##STR13## Wherein X is --O-- or--SO₂ --; m is 0 or 1; n is 0 or 1; q:r=10:15 to 15:10; p:q=1:100 to100:1; p+q+r=3 to 600 and preferably 30 to 200. The carbonyl groups ofthe moiety of Formula I or II are linked to the oxy groups of a moietyof Formula I or III; the oxy groups of the moiety of Formula I or IIIare linked to the carbonyl groups of the moiety of Formula I or II. Twocommercially available liquid crystalline copolyesters (obtained fromthe Carborundum Corporation) are Ekonol, a homopolymer of p-hydroxybenzoic acid, and Ekkcel, a copolymer of p-hydroxy benzoic acid,terephthalic and isophthalic acids, and 4,4'-biphenol. Other liquidcrystalline polyarylates of interest include a copolyester ofp-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid in a 75/25 molarratio and a copolyester obtained by polymerizing p-acetoxybenzoic acidin a polyethylene terephtalate matrix.

It should, of course, be obvious to those skilled in the art that otheradditives may be included in the blends of this invention. Theseadditives include plasticizers; pigments; flame retardants; reinforcingagents, such as glass fibers; thermal stabilizers; ultraviolet lightstabilizers; impact modifiers, and the like.

EXAMPLES

The following examples serve to give specific illustrations of thepractice of this invention but they are not intended in any way to limitthe scope of this invention.

The following designations are used in the examples and they have thefollowing meaning:

Polyarylate: A polymer having a repeat unit of the formula: ##STR14##having a reduced viscosity of 0.66 as measured in p-chlorophenol, 0.2g/100 ml at 49° C. (ARDEL™ D-100 obtained from Union Carbide Corp.)

Polyketone I: A polymer having a repeat unit of the formula: ##STR15##having a reduced viscosity of 1.2 as measured in 96% sulfuric acid (1wt. % solution) at 25° C. (PEEK obtained from Imperial ChemicalsIndustries, Ltd.)

EXAMPLE 1

80 weight percent of the Polyarylate was blended with 20 weight percentof Polyketone I in a single screw 1-inch diameter extruder with L/D=20/1at 360° C. The extrudate was chopped into pellets. The pelletizedproduct was injection molded in a 11/4 oz screw injection moldingmachine at temperatures of 350°-390° C. into ASTM test specimens. Thetest specimens were measured for the following properties: tensilemodulus, tensile strength, and percent elongation according to ASTMD-638, tensile impact strength according to ASTM D-1822, notched izodimpact strength according to ASTM D-256, and heat distortion temperatureaccording to ASTM D-648.

The results are shown in Table I together with the results of theunblended constituents.

EXAMPLE 2

The procedure of Example 1 was exactly repeated except that 75 weightpercent of Polyarylate was blended with 25 weight percent of PolyketoneI.

The results are shown in Table I.

EXAMPLE 3

The procedure of Example 1 was exactly repeated except that 60 weightpercent of Polyarylate was blended with 40 weight percent of PolyketoneI.

The results are shown in Table I.

EXAMPLE 4

The procedure of Example 1 was exactly repeated except that 50 weightpercent of Polyarylate was blended with 50 weight percent of PolyketoneI.

The results are shown in Table I.

EXAMPLE 5

The procedure of Example 1 was exactly repeated except that 40 weightpercent of Polyarylate was blended with 60 weight percent of PolyketoneI.

The results are shown in Table I.

                                      TABLE I                                     __________________________________________________________________________                                   Tensile                                                                             Notched Izod                                  Description of                                                                          Tensile                                                                            Tensile    Impact                                                                              Impact Strength                               the Composition                                                                         Modulus                                                                            Strength                                                                           Elongation                                                                          Strength                                                                            (ft.-lbs./in.                                                                         Heat Distortion                  Example                                                                            Polymer (wt. %)                                                                         (psi)                                                                              (psi)                                                                              (%)   (ft.-lb./in.sup.2)                                                                  of notch)                                                                             Temp. (°C.)               __________________________________________________________________________    Control                                                                            Polyketone I (100)                                                                      531,000                                                                            12,900                                                                             98    123   1.7     143                              Control                                                                            Polyarylate (100)                                                                       300,000                                                                            10,000                                                                             40    135   4.2     165                              1    Polyarylate (80)                                                                        318,000                                                                             9,850                                                                             67    120   6.2     --                                    Polyketone I (20)                                                        2    Polyarylate (75)                                                                        348,000                                                                            10,600                                                                             90    177   8.0     145                                   Polyketone I (25)                                                        3    Polyarylate (60)                                                                        342,000                                                                            10,600                                                                             87    193   9.1     --                                    Polyketone I (40)                                                        4    Polyarylate (50)                                                                        377,000                                                                            11,900                                                                             108   228   9.7     147                                   Polyketone I (50)                                                        5    Polyarylate (40)                                                                        366,000                                                                            10,400                                                                             78    129   3.3     --                                    Polyketone I (60)                                                        __________________________________________________________________________

EXAMPLE 6

60 weight percent of Polyketone I was blended with 40 weight percent ofa poly(arylate-carbonate) [(Lexan 3250) based on bisphenol A having anarylate/carbonate molar ratio of 87/13 and a tere/iso ratio of 73/27 forthe arylate part, hereinafter Poly(arylate-carbonate) I] was prepared ina single screw one inch diameter extruder with L/D=36/1 at 350°-360° C.The blend was injection molded and tested as described in Example 1.

The properties are listed in Table II.

EXAMPLE 7

60 weight percent of Polyketone I was blended with 40 weight percent ofa poly(arylate-carbonate) [(Lexan 4450) (40 wt. %) based on bisphenol Ahaving an arylate/carbonate molar ratio of 1/2 and a tere/iso ratio of87/13 for the arylate part, hereinafter Poly(arylate-carbonate) II] asdescribed in Example 6. The blend was injection molded and tested asdescribed in Example 1.

The results are listed in Table II.

                                      TABLE II                                    __________________________________________________________________________    Property Data for Poly(arylate-carbonate)/                                    Poly(arylether ketone) Blends                                                                          PAC-I    PAC-II                                      Sample Description                                                                           PAC-I.sup.1                                                                        PAC-II                                                                             60% Polyketone I                                                                       60% Polyketone I                            __________________________________________________________________________    Tensile Modulus (psi)                                                                        312,000                                                                            326,000                                                                            344,000  344,000                                     Tensile Strength (psi)                                                                        9,210                                                                              9,540                                                                              10,700   9,490                                      % Elongation   43   83   97       78                                          Notched Izod Impact Strength                                                                 3.6  9.0  9.4      13.8                                        (ft-lbs/in. of notch)                                                         Tensile Impact Strength                                                                      48   149  173      165                                         ft-lbs/in.sup.2                                                               __________________________________________________________________________     .sup.1 PAC = poly(acrylate carbonate)                                    

EXAMPLE 8

90 weight percent of Polyketone I was blended with 10 weight percent ofa liquid crystalline polyarylate (Ekkcel I-2000 obtained fromCarborundum hereinafter LC-I) based on biphenol, terephthalic acid, andp-hydroxybenzoic acid by the procedure of Example 6. The blend wasinjection molded and tested by the procedures described in Example 1.Additionally melt flow was measured according to ASTM D-1238 under theconditions as shown in Table III.

The results are shown in Table III.

EXAMPLE 9

80 weight percent of Polyketone I was blended with 20 weight percent ofthe liquid crystalline polyarylate of Example 8 by the procedure ofExample 6. The blend was injection molded and tested by the proceduresdescribed Example 1. Melt flow was measured according to ASTM D-1238under the conditions as shown in Table III.

The results are shown in Table III.

                                      TABLE III                                   __________________________________________________________________________    Liquid Crystalline Polyarylate/Poly(arylether ketone) Blends                                       90% Polyketone I                                                                       80% Polyketone I                                Sample Description                                                                           LC-I  10% LC-I 20% LC-I Polyketone I                           __________________________________________________________________________    Tensile Modulus (psi)                                                                        583,000                                                                             549,000  744,000  531,000                                Tensile Strength (psi)                                                                        10,000                                                                              12,800   13,700   12,900                                % Elongation   2.2   18.3     2.1      98                                     Tensile Impact Strength                                                                      --    47       33       123                                    ft-lbs/in.sup.2                                                               Notched Izod Impact Strength                                                                 0.9   1.7      1.2      1.7                                    (ft-lbs/in. of notch)                                                         Melt flow, 44 psi 400° C.                                                             142   2.5      0.6      2.8                                    Melt flow, 440 psi 400° C.                                                            Too high to                                                                         80       47       102                                                   determine                                                      __________________________________________________________________________

EXAMPLE 10

90 weight percent of Polyketone I was blended with 10 weight percent ofa liquid crystalline polyarylate based on 75/25 (molar ratio)p-hydroxybenzoic acid/6-hydroxy-2-naphthanoic acid and having a meltflow of 148 dg/min at 300° C. (44 psi) as per ASTM D-1238 in a brabenderat 370° C. The blend was compression molded in a 4×4×0.020 inch cavitymold at 370° C. The sample was tested for mechanical properties andfound to be tough and strong (tensile strength=13,100 psi). Thecrystallization kinetics of this blend and unblended polyketone I weredetermined using a Perkin-Elmer DSC-2 (differential scanningcalorimeter). The data are listed in Table IV.

                  TABLE IV                                                        ______________________________________                                        Calorimetric and Data.sup.1 on Polyketone/Liquid Crystalline                  Polyarylate Blend                                                                                  90% Polyketone I                                         Sample    Polyketone 10% LC-II    LC-II                                       ______________________________________                                        T.sub.m (°C.)                                                                    335        336                                                      ΔH.sub.f (cal/g)                                                                  8.8        7.4                                                      T.sub.c (°C.)                                                                    293        282                                                      ΔH.sub.c (cal/g)                                                                  12.0       10.9                                                     t.sub.c at 310° C.                                                               365        1090                                                     (seconds)                                                                     t.sub.c at 300° C.                                                               103        305                                                      (seconds)                                                                     t.sub.c at 290° C.                                                               61         133                                                      (seconds)                                                                     MF.sub.10 (400° C.),                                                             2.8        2.6          617*                                        44 psi                                                                        MF.sub.10 (400° C.),                                                             102        59           Too high to                                 440 psi                           measure                                     ______________________________________                                         *Measured at 350° C., flow too high at 400° C.                  .sup.1 Samples were heated at 10° C./min up to 380° C. to       determine T.sub.m and ΔH.sub.f. They were then cooled at 10°     C./min to determine T.sub.c and ΔH.sub.c. The t.sub.c (time to          crystallize) values were determined after heating the sample to               380° C. followed by cooling at ˜160° C./min to the        designated temperature. The t.sub.c value denotes the time to reach           maximum crystallization rate.                                            

EXAMPLE 11

A poly(aryl ether ketone) (25 wt. %) of the structure (hereinafterPolyketone II): ##STR16## with a reduced viscosity of 1.1 as measured at1 wt. % in 96 wt. % sulfuric acid at room temperature was blended with75 wt. % of the Polyarylate in a Brabender blender at 375° C. The samplewas compression molded at 375° C. in a 4×4×0.020 inch cavity mold. 1/8inch wide strips of material were shear cut from the compression moldedsample. A cotton swab was fastened to the center of the sample. Thesample was placed under a tensile stress. The cotton swab was saturatedwith an organic chemical environment and aluminum foil was placed aroundthe cotton to prevent evaporation of the environment. The time torupture was determined for several environments for the blend and forunblended Polyarylate. The data are listed in Table V. Data on thePolyarylate control and additional Polyarylate/Polyketone blends arealso listed in Table V.

                                      TABLE V                                     __________________________________________________________________________    Enviromental Stress Rupture Resistance                                                   Time to Rupture                                                                        80% Polyarylate                                                                        60% Polyarylate                                                                        40% Polyarylate                                                                        75% Polyarylate                Environment                                                                          Stress                                                                            100% Polyarylate                                                                       20% Polyketone I                                                                       40% Polyketone I                                                                       60% Polyketone I                                                                       25% Polyketone                 __________________________________________________________________________                                                   II                             Toluene                                                                              500 psi                                                                           2 sec R  10 sec R 0.92 hr R                                                                              1 hr NCNB                                                                              62 sec R                       Xylene 500 psi                                                                           2 sec R  12 sec R 1 hr C&B 1 hr NCNB                                                                              76 sec R                       Ethyl Acetate                                                                        500 psi                                                                           1 sec R   4 sec R 1 hr C&B 1 hr NCNB                                                                              12 sec R                       Acetone                                                                              500 psi                                                                           1 sec R   7 sec R 1 hr NCNB                                                                              1 hr NCNB                                                                              34 sec R                       __________________________________________________________________________     R = ruptured                                                                  C&B = crazed and brittle                                                      NCNB = not crazed, not brittle                                           

DISCUSSION OF THE TEST RESULTS

The mechanical property data for polyarylate-poly(aryl ether ketone)blends demonstrate utility over the entire composition range. However,the range of 0-50 wt. % poly(aryl ether ketone) yields synergisticmechanical behavior in that the impact strength data for the blends(both notched izod impact strength and tensile impact strength) aresignificantly higher than the unblended constituents of the blend.

The blends containing liquid crystalline polyarylate exhibit excellentstrength. In the case of the p-hydroxybenzoic acid/6-hydroxy-2-naphthoicacid 75/25 copolymer, the decreased rate of crystallization (as shown bythe T_(c) and t_(c) values) indicates a level of interaction of theliquid crystalline polyarylate and the poly(aryl ether ketone).

Surprisingly, the melt viscosity of polyaryl ketone increases withaddition of liquid crystalline polyarylate. This is unexpected from thecomparison of constituent melt viscosities and totally disagrees withthe results described in U.S. Pat. No. 4,438,236.

The addition of poly(aryl ether ketone) to polyarylate yieldssignificant improvements in the environmental stress rupture resistance.

These property advantages indicate the blends of poly(aryl etherketones) and polyarylate exhibit unexpected synergistic behaviour inimpact strength for polyarylates and tensile strength for liquidcrystalline polyarylates. This combination of properties lead to aunique class of polymeric materials.

What is claimed is:
 1. A blend comprising a crystalline poly(aryl etherketone) and a liquid crystalline polyarylate selected from the groupconsisting of:(a) a homopolymer of p-hydroxybenzoic acid, (b) acopolymer of p-hydroxybenzoic acid, terephthalic and isophthalic acidsand 4,4'-biphenol, (c) a copolymer of p-hydroxybenzoic acid and6-hydroxy-2-naphthoic acid in a 75/25 molar ratio, (d) a copolyesterobtained by polymerizing p-acetoxybenzoic acid in a polyethyleneterephthalate matrix and; (e) a copolymer of p-hydroxybenzoic acid,terephthalic acid and 4,4'-biphenol.
 2. A blend as defined in claim 1wherein the poly(aryl ether ketone) is present in amounts of from about5 to about 95 weight percent.
 3. A blend as defined in claim 1 whereinthe liquid crystalline polyarylate is used in amounts of from about 5 toabout 95 weight percent.
 4. A blend as defined in claim 1 wherein thepoly(aryl ether ketone) has a repeating unit of the following formula:##STR17## wherein Ar is independently a divalent aromatic radicalselected from phenylene, biphenylene or naphthylene, X is independently##STR18## or a direct bond and n is an integer of from 0 to
 3. 5. Ablend as defined in claim 1 wherein the poly(aryl ether ketone) has arepeating unit of the following formula: ##STR19## wherein X isindependently ##STR20## or a direct bond.
 6. A blend as defined in claim1 wherein the poly(aryl ether ketone) has a repeating unit of theformula: ##STR21##
 7. A blend as defined in claim 1 wherein thepoly(aryl ether ketone) has a repeating unit of the formula: ##STR22##8. A blend as defined in claim 1 wherein the poly(aryl ether ketone) hasa repeating unit of the formula: ##STR23##
 9. A blend as defined inclaim 1 wherein the poly(aryl ether ketone) has a repeating unit of theformula: ##STR24##
 10. An injection molded article made from the blendof claim
 1. 11. A blend as defined in claim 1 wherein the poly(arylether ketone) has a repeating unit of the following formula: ##STR25##wherein a is an integer of 1 to 4 and b, c, and d are 0 or
 1. 12. Ablend as defined in claim 1 wherein the poly(aryl ether ketone) has arepeating unit of the following: ##STR26## wherein Ar is a divalentaromatic radical selected from phenylene, biphenylene or naphthylene, Xis independently ##STR27## or a direct bond and e is 0 or
 1. 13. A blendas defined in claim 1 wherein the poly(aryl ether ketone) has arepeating unit of the following formula: ##STR28## wherein Ar is adivalent aromatic radical selected from phenylene, biphenylene ornapthylene, X is independently ##STR29## or a direct bond and e is 0or
 1. 14. A blend as defined in claim 1 wherein the poly(aryl etherketone) has a repeating unit of one or more of the following: ##STR30##15. A blend comprising a crystalline poly(aryl ether ketone) and aliquid crystalline polyarylate of recurring moieties of Formulae I, IIand III: ##STR31## wherein X is --O-- or --SO₂ --; m is 0 or 1; n is 0or 1; q:r=10:15 to 15:10; p:q=1:100 to 100:1; p+q+r=3 to 600; thecarbonyl groups of the moiety of Formula I or II are linked to the oxygroups of a moiety of Formula I or III; the oxy groups of the moiety ofFormula I or III are linked to the carbonyl groups of the moiety ofFormula I or II.